Alan Howells gave evidence for three-and-a-half hours at a hearing of the General Teaching Council for Wales yesterday, where he is accused of “unacceptable professional conduct” in dealing with the allegations.

Mr Howells, ex head of Ysgol y Gogarth, Llandudno, said the staff were “lucky” to keep their jobs after a disciplinary hearing. “I could have gone either way with it. I was absolutely horrified at their behaviour,” he told the hearing in Ewloe.

Mr Howells, who was head from 2004 until 2009, disputed telling the disciplinary panel that they couldn’t sack the teaching assistants. “I categorically refute it,” he declared.

Ysgol Y Gogarth, Llandudno

Questioned by GTCW presenting officer Louise Price, Mr Howells claimed Conwy councillor Cheryl Carlisle, who as a governor sat on the 2007 disciplinary panel, had an “agenda” against him.

It has been claimed the two men and two women teaching assistants had been drunk and there was kissing and other antics. They had received final written warnings.

Mr Howells accused Cllr Carlisle of “bullying” and claimed she had decided to form a “splinter group”.

He is alleged to have failed to record the full details of the allegations made to him by two members of staff who were on the trip, and sought to “unduly influence” the decision of the school disciplinary panel. It’s also claimed he failed to ensure that child protection procedures were followed.

Mr Howells, who wasn’t on the trip, maintains he had followed advice “in good faith”.

No culture of drinking

Quizzed by his counsel Martin Downs, Mr Howells, who has been working in Hong Kong, said he had learned “absolute masses” from his experience.

He denied there was a “culture of drinking” among the school’s 135 staff.

Former chairman of the governors, Hilary Roberts, said when Mr Howells was appointed he had been the “outstanding candidate”, adding: “He had a clear vision of how to take the school forward. I was particularly impressed with the way he engaged with children.”

She insisted Mrs Carlisle’s suggestion of a culture of drinking was “wholly unwarranted”.

After the furore about the school trip, Mrs Roberts said: “Alan was very concerned to ensure there was a full and independent investigation into the conduct. Alan was very concerned any investigation should be independent and therefore credible.”

“My recollection is that two staff members were drunk, semi dressed and engaged in some form of sexual behaviour.”

The witness said Mrs Carlisle’s attitude towards Mr Howells was good until a year or so after the disciplinary proceedings and it became known “Alan had an extramarital affair”.

The councillor made “entirely unfounded allegations” against the headteacher. “Cheryl Carlisle’s constant onslaught and persistent phone calls made me unwell,” she claimed.

Hilary Roberts denied having tried to “play down” what happened on the trip. She said: “We wanted to avoid the staff room gossip. We were not playing it down so much as trying to control the whole incident while the investigation was taking place.”